.yellow {
        /* padding 会改变元素宽高，需要减去 padding */
        background-color: yellow;
        width: 700px;
        height: 200px;
        /* 内边距 */
        padding: 50px 50px;
        margin-bottom: 10px;
}

.aqua {
    background-color: aqua; 
    width: 700px; 
    height: 200px;
}

.green{
    background-color: green;
    margin-bottom: 10px;
    width: 700px;
    height: 200px;
    padding: 50px 50px;
    position: relative;
}

.blue{
    background-color: blue;
    margin-bottom: 10px;
    width: 800px;
    height: 300px;
}



.red{
    background-color: red;
    width: 340px;
    height: 200px;
    position: absolute;
    top: 50px;
    left: 50px;
}

.pink{
    background-color: pink;
    width: 340px;
    height: 200px;
    position: absolute;
    top: 50px;
    right: 50px;
}
